Various prior art patents describe storage spaces that are provided beneath the vehicle floor. One example of a vehicle having a rear cargo space beneath the floor is described in U.S. Pat. No. 3,325,207. This patent describes a hidden cargo storage area which is designed into the body of the vehicle and is provided with a pivoting floor section which covers the hidden cargo storage area. The hidden cargo storage area is designed to accommodate a wheel and other cargo.
Similarly, U.S. Pat. No. 5,257,846 discloses a luggage space which is located behind a rear seat of a station wagon type vehicle.
U.S. Patent Application Publication 2004/0100116, to Rhodes et al, published May 27, 2004, and hereby incorporated by reference in its entirety, describes a vehicle seating structure which is foldable and collapsible for storage inside a tub which is disposed at least partially in a floor of the vehicle. Such a tub may be configured to conceal the second and third row passenger seats in a mini van. In this configuration, the tub must be strong enough to hold approximately 400 lbs. of weight, which limits the material selection to steel or other metal products. Due to the size of the collapsed seats to be stored in the tubs, substantial manufacturing challenges are presented in forming such a large stamped steel component.
Additionally, the shape of such a tub renders it susceptible to noise radiation which, if untreated, presents undesirably loud cabin noise which creates a poor environment for the driver and passengers. Traditional means for quieting automobiles would include mastics, doubler panels, spray-on deadener, fiberglass matting, etc. Each of these systems has its shortcomings.
Mastics are asphaltic patches which are attached to vertical metal surfaces and hardened during a heat-elevated painting process. Heat activated mastics are also used for damping resonances. Disadvantages of mastics include: build variations between vehicles due to manual placement; airborne paint contamination resulting in paint quality issues; labor required for installation; inconsistent melt characteristics; non recyclability; susceptibility to damage during installation; interior packaging limitations due to thickness of mastics; providing only localized damping; and assembly line space requirements.
Doubler panels include a stamped panel which is welded to a body structure panel. An expandable asphaltic material is sandwiched between the stamping and body structure components. The sandwiched material expands and hardens when processed through the vehicle paint shop. Disadvantages of this configuration include the additional tooling required to manufacture the doubler, the welding operation required for attachment, interior packaging limitations due to thickness of the doubler, and localized damping only in the area of the doubler panel.
Spray-on deadeners are sprayed treatments which are applied via a robot to the underbody structure sheet metal components on a vehicle. Spray-on deadeners provide a noise control barrier. Disadvantages of spray-on deadeners include: masking requirement for spray applications; non-recyclability; process limited by overspray and dripping; robot requirement for application; paint shop contamination; labor on assembly line space requirement; on-going maintenance of robots; and only localized dampening coverage.
Fiberglass matting provides fiberglass parts which are formed to the contour of the body component and attached during a vehicle assembly. These acoustic treatments are often used to reduce high frequency air-borne vehicle noise. Disadvantages of fiberglass matting include labor and assembly space requirements; fastener requirements; interior packaging limitations due to thickness; and the added expense and weight of the fiberglass parts.